When to use a cookie, and when to use a ruler: A response to Byers-Heinlein, Bergmann and Savelei’s “Six solutions for more reliable infant research”

Here we provide a response of broad agreement to the authors’ six suggestions for improving the reliability of infant research. We also draw attention to three points we feel are important additions. We discuss the importance of considering measurement validity alongside measurement reliability as both contribute to overall measurement error, as well as emphasizing the selection of methods that are theory driven and balancing this with the need for precise or accurate measures. We also briefly discuss how differences in training, access to resources and other factors can influence choices of method and analysis. Sometimes simple is good enough.